ASTM A 668

This specification covers standard requirements for weldedaustenitic stainless steel feedforward heater tubes including those bent, ifspecified, into the form of U-tubes for application in tubular feed-waterheaters. All finished straight tubing or straight tubing ready for U-bendingshall be furnished in the solution-annealed condition. The steel shall conformto the required chemical composition for carbon, phosphorus, chromium,molybdenum, nitrogen, and copper. The material shall also conform to tensileproperties such as tensile strength, yield strength, and elongation. The steelshall undergo mechanical tests such as tension test, hardness test, reversebend test, flattening test, flange test, pressure test, hydrostatic test, andair underwater test. Nondestructive test (electric test) shall be performed andcorrosion resisting properties shall be determined for each sample tube.

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